1. Field of the Invention
The present invention relates to a flow control valve for liquids. More particularly, the present invention relates to a flow control valve having a compact structure and that is operable between on and off positions by a movable arm, for example an arm that is responsive to the force of a moving gas stream, such as an airflow stream, or to the level of a float in a liquid reservoir.
2. Description of the Related Art
Flow control valves of many different structural designs have been developed over the years. And their actuation methods have also been of different forms. For example, in connection with spray cooling systems for air conditioning and refrigeration units, water flow control can be controlled by a valve that has a paddle placed in the path of an air stream to sense when the condensing unit fan is in operation, and thus when spray cooling of the condenser can be beneficial.
An example of one such spray cooling arrangement is disclosed in U.S. Pat. No. 6,438,977, which issued on Aug. 27, 2002, to McKay. The flow control valve includes an axially reciprocable plunger that is movable toward and away from a valve seat into and out of a water-flow-blocking position, based upon movement of a paddle in response to the force provided upon initiation of a flow of air against the paddle. The airflow is generated by a cooling fan for blowing cooling air across the coils of the condenser. However, the valve that is illustrated and described in that patent is controlled based only upon airflow, and it operates independently of the ambient temperature. Thus, it allows cooling water flow at times when such flow is not needed, such as at lower ambient temperature conditions when the cooling air flow itself is sufficient for adequate condenser coil cooling. When operated unnecessarily, such an arrangement wastes water and thereby adds to the operating cost of the system.
Additionally, the McKay valve is an axially operated valve. In that valve structure the flow shutoff member is moved axially toward and away from an orifice through which the water flows. It thus must be moved into a closed, no-flow position by a larger force that is sufficient to overcome the force resulting from the upstream water pressure that acts against the facing surface of the shutoff member. Accordingly, either a longer paddle lever arm is needed, or a larger paddle surface area against which the airflow stream impinges must be provided, in order to overcome the upstream pressure force.
Other axially-operated valve members in refrigeration unit spray cooling systems are disclosed in U.S. Pat. No. 4,274,266, which issued on Jun. 23, 1981, to Shires; and in U.S. Pat. No. 6,105,376, which issued on Aug. 22, 2000, to Stewart et al.
There is therefore a need for an inexpensive and simple liquid flow control valve having a simple structure and that is responsive to both an air flow stream as well as to ambient temperature conditions, so that it only operates when needed. There is also a need for an inexpensive and simple liquid flow control valve that can be operated by a lever-mounted float member to control a liquid level in a liquid reservoir.